1. Field of the Invention
The invention relates to a fish filleting apparatus, which, in general, enables the severing of muscle flesh from fish, and, in particular, to an apparatus for cutting off the muscle flesh of fish opened at their belly, which apparatus comprises a conveyor equipped with conveying saddles for receiving the fish individually engaging them within their belly cavity, and for conveying said fish with the tail leading, and further at least one belly filleting tool, one back filleting tool and one severing tool, which tools include pairs of circular knives, respectively, which are driven, arranged symmetrically with regard to the path of the conveying saddles, and designed to cut into the fish at both sides of the belly and back spokes up to the backbone, and for cutting in the region of the flanks of the backbone, respectively.
2. Prior Art
An apparatus of this type can be taken, for example, from German Patent Publication 14 54 087. With regard to the knife arrangement, this patent shows a conventional filleting machine in which the fish are mounted onto pushing saddles by means of their opened belly cavities and are conveyed with their tails leading through the working area of the filleting tools. These comprise belly and back knives, flank knives and severing knives, respectively, arranged in pairs along the path of the pushing saddles, as well as pairs of guiding plates or guiding rails in the area behind the belly and back knives. With this apparatus standard fish fillets, i.e. fillets which merely contain the pinbones present above the belly cavity region, can be obtained at high yield.
Up to the present, consumer habits have been maintained based on product forms which have originated partly from manual production and/or take into consideration needs and/or requirements, respectively, which facilitate subsequent refining steps or even make them possible
Awareness of tradition and quality in respect of various of these product forms leads finally to the fact that consumers consider these to be either proof of quality, e.g. with regard to the manner of production (done by hand), or evidence of the production quality Under these circumstances, the type of mechanical production striven for today must take into consideration that the product obtained cannot be distinguished from one produced in the "traditional" manner.
Thus, in certain fields of consumption, a fish product is required which, in contrast to a fish fillet, is called a fish side. A fish side of this type is obtained, like the fish fillet, through the belly and back filleting cuts, although then the ribs encompassing the belly region are severed from the vertebral column and remain in the muscle flesh A product of this type can easily be produced by hand and has the advantage of effecting a stabilization in a smoking process. Furthermore, high yield and, in fact, a greater sales' weight are both obtainable.
Apparatuses are known for mechanized obtainment of such fish sides, but the product obtained in this manner is dissatisfactory with regard to the above-mentioned criteria.
Thus, from U.S. Pat. No. 1 682 418 an apparatus can be taken in which, beginning at the root of the tail, the fish sides are severed from the skeleton by oscillating knives whilst being conveyed by means of pairs of rollers, Which engage the bone framework progressively exposed by means of cutting/severing of the meat therefrom. During this process, the ribs are also cut off. In this process, although the spacing of the knives is controlled corresponding to the thickness of the vertebral column, it is, however, obvious that the flesh yield is not satisfactory, because the slice of fish containing the backbone together with the belly and back spokes has, respectively, the thickness of the vertebral column, which means that valuable fish flesh remains on the thinner belly and back spokes
Similar conditions are also inherent in a product obtained with an apparatus shown in German published patent application 27 00 068, according to which disclosure the waste slice, having a thickness corresponding to that of the backbone and containing the backbone together with the belly and back spokes, is cut out. In this apparatus, adjustment of the spacing of the knives follows, under the influence of the change in the braking torque acting on the knives, which force is caused by the friction of the vertebrae on the knife flanks.
3. Objects of the Invention
It is therefore the primary object of the present invention to suggest an apparatus which obviates the prior art setbacks in the production of fish sides of the type described above.
It is a further and extremely important object of the present invention to specifically suggest an apparatus enabling the highest-yield obtainment of fish sides.
It is still another highly relevant and prominent object of the invention to enable the mechanical gaining of a fish side product in such a manner that the appearance thereof is comparable to that of a manually obtained product.